Without limiting the scope of the present invention, its background will be described in relation to reservoir stimulation operations performed from a wellbore that traverses a hydrocarbon bearing subterranean formation, as an example.
It is well known in the well drilling and completion art that hydraulic fracturing of a hydrocarbon bearing subterranean formation is sometimes desirable to increase the permeability of the reservoir formation in the production interval or intervals adjacent to the wellbore by performing a stimulation operation. According to conventional practice, a fracture fluid such as water, oil, oil/water emulsion, gelled water, gelled oil, carbon dioxide and nitrogen foams, water/alcohol mixtures or the like is pumped down the work string with sufficient volume and pressure to open the desired fractures in the reservoir formation. In addition, during certain stages of the fracturing operation, the fracture fluid may carry a suitable propping agent, such as sand, gravel or engineered proppants, which are deposited into the fractures and serve the purpose of holding the fractures open following the fracturing operation.
During the fracturing operation, the fracture fluid must be pumped into the formation at a flow rate that is sufficiently high enough to generate the required pressure to fracture the reservoir formation and allow the entrained proppants to enter the fractures and prop the formation structures apart. As such, the proppants in the fractures create highly conductive paths from the reservoir formation to the wellbore. Importantly, the success of the fracturing operation is dependent upon the ability to inject large volumes of hydraulic fracture fluid into desired locations within the reservoir formation at a high pressure and high flow rate.
It has been found, however, that it is difficult to achieve the desired stimulation in certain completions, such as long horizontal completions, due to uncertainty regarding fracture initiation and fracture propagation in the reservoir formation after performing conventional perforating operations. Accordingly, a need has arisen for an improved perforating and fracturing method that is operable to create communication tunnels through the casing and into the reservoir formation for fluid production. A need has also arisen for such an improved perforating and fracturing method that is operable to reduce the uncertainty regarding fracture initiation and fracture propagation in the reservoir formation.